Aussie Lapidary Forum

LAPIDARY => Ask a "Silly" Question => Topic started by: goltzy75 on March 07, 2020, 11:06:27 PM

Title: Laps kit for cutting sapphire
Post by: goltzy75 on March 07, 2020, 11:06:27 PM
Hi All!
Just wondering if anyone can help me. I would like to know what laps I would need to cut sapphire? As well as any other tools etc. to make a basic kit. Silly and generic  question but I am totally new. I have been given a gem master( machine only) discs,dops etc not included.
Thanks for your help
Title: Re: Laps kit for cutting sapphire
Post by: Lowjiber on March 08, 2020, 12:53:12 AM
As you know, Sapphire is hard (Mohs 9).  However, that makes cutting easier in my opinion.  Just the "standard" range of grits is all one needs.

I recommend grit sizes of 600, 1200, and 3000 (pre-polish).  Polishing laps are pretty much a matter of preference, but you'll need diamond... either as a powered (bort) or the Pandemonium sticks by Gearloose.

The Pandemonium sticks are becoming very popular.  After a pre-polish with your 3000# grit disk, use 8,000 & 60,000 sticks.

Polishing disks widely vary from person to person.  I like Gearloose polishing laps... Batt Lap, Zinc+.  Visit the Gearloose webpage where there is a lot of info on various polishing disks.

Lubricant for polishing also varies... from Snake Oil to WD-40 and everything in between.  You'll find that everyone has a favorite.  I generally use Snake Oil on the Batt Laps, but that's just me.

While I'm rambling, let me suggest "learning" to cut with something cheap and hard like CZ before getting busy with the more valuable sapphire. beers
Title: Re: Laps kit for cutting sapphire
Post by: goltzy75 on March 08, 2020, 08:50:06 AM
Thankyou Lowjiber!
Title: Re: Laps kit for cutting sapphire
Post by: MakkyBrown on March 08, 2020, 10:23:12 AM
As you know, Sapphire is hard (Mohs 9).  However, that makes cutting easier in my opinion.  Just the "standard" range of grits is all one needs.

I recommend grit sizes of 600, 1200, and 3000 (pre-polish).  Polishing laps are pretty much a matter of preference, but you'll need diamond... either as a powered (bort) or the Pandemonium sticks by Gearloose.

The Pandemonium sticks are becoming very popular.  After a pre-polish with your 3000# grit disk, use 8,000 & 60,000 sticks.

Polishing disks widely vary from person to person.  I like Gearloose polishing laps... Batt Lap, Zinc+.  Visit the Gearloose webpage where there is a lot of info on various polishing disks.

Lubricant for polishing also varies... from Snake Oil to WD-40 and everything in between.  You'll find that everyone has a favorite.  I generally use Snake Oil on the Batt Laps, but that's just me.

While I'm rambling, let me suggest "learning" to cut with something cheap and hard like CZ before getting busy with the more valuable sapphire. beers
For sapphire if you use 1200 I'd not worry about using 3k, go 1200 to 6-8k. But then it is a mater of figuring out what works for each of us.

CheersMB
Title: Re: Laps kit for cutting sapphire
Post by: Lowjiber on March 09, 2020, 12:14:43 AM
@goltzy75... Since your original post dealt with sapphire, @MakkeyBrown and I have commented on using diamond to polish.  However, as you broaden your range of stones to be faceted you'll likely find that many of your fellow-faceters use oxide polishes for stones that are Mohs 7, or below.

For example, a piece of quartz (Mohs 7) will polish perfectly using Cerium Oxide (CeOx).  Oxides use water, vice oils, as a lubricant.  The two most popular are CeOx and Alumina Oxide.

The forum's sponsor, Aussie Sapphires, sells a wide range of GearLoose laps.  One of the best for using oxides is the famous DarkSide lap.  If you'll go to the link below, there is a lot of information from GearLoose regarding use of the DarkSide laps.
https://www.aussiesapphire.com.au/darkside-polishing-lap-from-gearloose (https://www.aussiesapphire.com.au/darkside-polishing-lap-from-gearloose)

Just food-for-thought...

John
Title: Re: Laps kit for cutting sapphire
Post by: MakkyBrown on March 13, 2020, 12:08:15 AM
Hi Lowjiber, There are so many ways to go about cutting/polishing, it's just finding what works for you as a facetor. For me I've not found anything I can't polish on a tin lap with a small amount of thick 100k diamond/wax mix. Including quartz. I find it is very important to keep my sintered cutting lap sharp, then I don't get as many problems with pitting/scratching, and makes prepolish/polish a lot easier.
I think I remember reading Jeff Graham had good things to say about tin laps.
I have some lithium niobate, that might be a good test for the 100k tin lap, been meaning to cut it for awhile.

CheersMB
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